For illegal interests, water is added into cow milk, which leads to the reduction of various indexes. In order to increase these indexes and reach cow milk quality standards, after water, various additives are blended into cow milk and mixed repeatedly. The five additives used most frequently are as follows: fatty oil (to enhance fat index), protein (to enhance protein index), dextrin and whey powder (to enhance various indexes), melamine (to enhance various indexes, in particular the protein index). Blending melamine into cow milk could result in serious consequences, such as pediatric renal calculus.
Currently, protein in milk is detected mainly by determining the nitrogen content. Therefore, as a nitrogen-containing compound, melamine was added to counterfeit protein. In addition, using the existing detecting methods, it is difficult to detect illegal additives such as bean flour, animal hair until serious consequences are caused.
Consequently, an ideal method for detecting the quality of cow milk should detect a substance that stably exists in cow milk, and the concentration of which will be reduced or changed upon dilution but cannot be manipulated by additives.
Summing up, it is urgent to develop the ideal method for detecting the quality of cow milk and other related products.